Computational Thinking Jeannette M Wing Assistant Director Computer

Computational Thinking Jeannette M. Wing Assistant Director Computer and Information Science and Engineering Directorate National Science Foundation and President’s Professor of Computer Science Carnegie Mellon University St. Joseph’s University Philadelphia, Pennsylvania October 8, 2009

My Grand Vision • Computational thinking will be a fundamental skill used by everyone in the world by the middle of the 21 st Century. – Just like reading, writing, and arithmetic. – Incestuous: Computing and computers will enable the spread of computational thinking. – In research: scientists, engineers, …, historians, artists – In education: K-12 students and teachers, undergrads, … J. M. Wing, “Computational Thinking, ” CACM Viewpoint, March 2006, pp. 33 -35. Paper off http: //www. cs. cmu. edu/~wing/ Computational Thinking 2 Jeannette M. Wing

Computing is the Automation of Abstractions Automation Computational Thinking focuses on the process of abstraction - choosing the right abstractions - operating in terms of multiple layers of abstraction simultaneouslyas in - defining the relationships the between layers Mathematics guided by the following concerns… Computational Thinking 3 Jeannette M. Wing

Measures of a “Good” Abstraction in C. T. as in Engineering • Efficiency NEW – How fast? – How much space? – How much power? • Correctness – Does it do the right thing? • Does the program compute the right answer? – Does it do anything? • Does the program eventually produce an answer? [Halting Problem] • -ilities – – – Simplicity and elegance Usability Modifiability Maintainability Cost … Computational Thinking 4 Jeannette M. Wing

Computational Thinking, Philosophically • Complements and combines mathematical and engineering thinking – C. T. draws on math as its foundations • But we are constrained by the physics of the underlying machine – C. T. draws on engineering since our systems interact with the real world • But we can build virtual worlds unconstrained by physical reality • Ideas, not artifacts – It’s not just the software and hardware that touch our daily lives, it will be the computational concepts we use to approach living. • It’s for everyone, everywhere Computational Thinking 5 Jeannette M. Wing

Sample Classes of Computational Abstractions • Algorithms – E. g. , mergesort, binary search, string matching, clustering • Data Structures – E. g. , sequences, trees, graphs, networks • State Machines – E. g. , finite automata, Turing machines • Languages – E. g. , regular expressions, …, VDM, Z, …, ML, Haskell, …, Java, Perl • Logics and semantics – E. g. , Hoare triples, temporal logic, modal logics, lambda calculus • Heuristics – E. g. , A* (best-first graph search), caching • Control Structures – Parallel/sequential composition, iteration, recursion • Communication – E. g. , synchronous/asynchronous, broadcast/P 2 P, RPC, shared memory/message-passing • Architectures – E. g. , layered, hierarchical, pipeline, blackboard, feedback loop, client-server, parallel, distributed • … Computational Thinking 6 Jeannette M. Wing

Examples of Computational Thinking in Other Disciplines Computational Thinking 7 Jeannette M. Wing

One Discipline, Many Computational Methods Computational Thinking 8 Jeannette M. Wing

Computational Thinking in Biology • Shotgun algorithm expedites sequencing of human genome • DNA sequences are strings in a language • Boolean networks approximate dynamics of biological networks • Cells as a self-regulatory system are like electronic circuits • Process calculi model interactions among molecules • Statecharts used in developmental genetics • Protein kinetics can be modeled as computational processes • Robot Adam discovers role of 12 genes in yeast • Page. Rank algorithm inspires ecological food web Computational Thinking 9 Credit: Wikipedia Jeannette M. Wing

Model Checking Primer Finite State Machine model M Temporal Logic property F AG p AF p, EG p, EF p M’s computational tree Model Checker yes counterexample is falsified here. Computational Thinking 10 Jeannette M. Wing

Model Checking Problem Let M be a finite state machine. Let be a specification in temporal logic. Find all states s of M such that: M, s Efficient algorithms: [CE 81, CES 86, Ku 94, QS 81, VW 94] Efficient data structures: binary decision diagrams [Br 86] Computational Thinking 11 Jeannette M. Wing

Model Checking in Biology Goal: Predict Rate of Folding of Proteins 1. Finite State Machine M represents 3 -residue protein 1’. BDD efficiently represents M Method easily handles proteins up to 76 residues. 2. Temporal Logic Formula a. Will the protein end up in a particular configuration? b. Will the second residue fold before the first one? c. Will the protein fold within t ms? d. What is the probability that (c)? e. Does the state s have k folded residues and have energy c? Model checking can explore state spaces as large as 276 1023, 14 orders of magnitude greater than comparable techniques [LJ 07]. Computational Thinkingfor FKBP-12, Computed via 12 Energy Profile Method Jeannette M. Wing

One Computational Method, Many Disciplines Machine Learning has transformed the field of Statistics. Computational Thinking 13 Jeannette M. Wing

Machine Learning in the Sciences Astronomy - Brown dwarfs and fossil galaxies discovery via machine learning, data mining, data federation - Very large multi-dimensional datasets analysis using KD-trees Credit: SDSS Medicine - Anti-inflammatory drugs - Chronic hepatitis - Mammograms - Renal and respiratory failure Meteorology Credit: Live. Science - Tornado formation Neurosciences CT & TC Credit: Eric Nguyen, Oklahoma University - f. MRI data analysis to understand language via machine learning 14 Jeannette M. Wing

Machine Learning Everywhere Supermarkets Credit Cards Wall Street Entertainment: Shopping, Music, Travel Computational Thinking Credit: Wikipedia Sports 15 Jeannette M. Wing Credit: Wikipedia

Computational Thinking 16 Jeannette M. Wing

? Computational Thinking 17 Jeannette M. Wing

Computational Thinking 18 Jeannette M. Wing

Question (Kearns): Can a Set of Weak Learners Create a Single Strong One? Answer: Yes, by Boosting Algorithms (e. g. , [FS 99]) Computational Thinking 19 Jeannette M. Wing

Computational Thinking 20 Jeannette M. Wing

Computational Thinking 21 Jeannette M. Wing

Computational Thinking 22 Jeannette M. Wing

Computational Thinking 23 Jeannette M. Wing

Computational Thinking 24 Jeannette M. Wing

Computational Thinking 25 Jeannette M. Wing

Computational Thinking 26 Jeannette M. Wing

Computational Thinking in the Sciences and Beyond Computational Thinking 27 Jeannette M. Wing

CT in Other Sciences, Math, and Engineering - Atomistic calculations are used to explore chemical phenomena - Optimization and searching algorithms identify best chemicals for improving reaction conditions to improve yields Chemistry Mathematics [York, Minnesota] - Discovering E 8 Lie Group: 18 mathematicians, 4 years and 77 hours of supercomputer time (200 billion numbers). Profound implications for physics (string theory) - Four-color theorem proof Credit: Wikipedia Engineering (electrical, civil, mechanical, aero & astro, …) Credit: Boeing - Calculating higher order terms implies more precision, which implies reducing weight, waste, costs in fabrication - Boeing 777 tested via computer simulation alone, not in a wind tunnel Computational Thinking 28 Jeannette M. Wing

CT for Society Economics - Automated mechanism design underlies electronic commerce, e. g. , ad placement, on-line auctions, kidney exchange - Internet marketplace requires revisiting Nash equilibria model - Use intractability for voting schemes to circumvent impossibility results - Stanford CL approaches include AI, temporal logic, state machines, process algebras, Petri nets Law - POIROT Project on fraud investigation is creating a detailed ontology of European law - Sherlock Project on crime scene investigation - Writing legal documents akin to programming, e. g. , parameter passing Humanities - What could you do with a million books? Nat’l Endowment for the Humanities Inst of Museum and Library Services Computational Thinking 29 Jeannette M. Wing

What About Our Planet (Geosciences)? Computational Thinking: - Abstractions for Sky, Sea, Ice, Land, Life, People, etc. - Hierarchical, composable , modular, traceability, allowing multiple projections along any dimension, data element, or query - Well-defined interfaces user Credit: NASA interface implementation Computational Thinking 30 Jeannette M. Wing

Educational Implications Computational Thinking 32 Jeannette M. Wing

Pre-K to Grey • K-6, 7 -9, 10 -12 • Undergraduate courses – Freshmen year • “Ways to Think Like a Computer Scientist” aka Principles of Computing – Upper-level courses • Graduate-level courses – Computational arts and sciences • E. g. , entertainment technology, computational linguistics, …, computational finance, …, computational biology, computational astrophysics • Post-graduate – Executive and continuing education, senior citizens – Teachers, not just students Computational Thinking 33 Jeannette M. Wing

Education Implications for K-12 Question and Challenge for the Computing Community: What is an effective way of learning (teaching) computational thinking by (to) K-12? - What concepts can students (educators) best learn (teach) when? What is our analogy to numbers in K, algebra in 7, and calculus in 12? - We uniquely also should ask how best to integrate The Computer with teaching the concepts. Computer scientists are now working with educators and cognitive learning scientists to address these questions. Computational Thinking 34 Jeannette M. Wing

Recursion: Towers of Hanoi Goal: Transfer the entire tower to one of the other pegs, moving only one disk at a time and never a larger one onto a smaller. Computational Thinking 35 Jeannette M. Wing

Data Abstraction and Representation people waiting in queue Credit: Wikipedia stack queue tree (upside down) representation invariant array and pointer Computational Thinking 36 Jeannette M. Wing

Composition and Decomposition Credit: The LEGO Group Credit: Meccano Computational Thinking 37 Jeannette M. Wing

Sorting and Search Computational Thinking 38 Jeannette M. Wing

Intractability: Traveling Salesman Problem: A traveling salesperson needs to visit n cities. Is there a route of at most d in length? O(n!) n = 16 242 days n = 25 5 x 10^15 centuries Computational Thinking 39 Jeannette M. Wing

Undecidability: Tiling Can we tile the entire plane Z 2? Example from David Harel Computational Thinking 40 Jeannette M. Wing

Data as Code and Code as Data unrecognized email attachment Computational Thinking 41 Jeannette M. Wing

Correctness: Avoiding Bugs to Save Money and Lives Credit: ESA Ariane 5 failure Credit: BYTE Magazine Intel Pentium FPU error Credit: Intel Now Microsoft uses formal verification. Now Intel uses formal verification. Computational Thinking 42 Jeannette M. Wing

Caching home Computational Thinking Credit; Wikipedia locker 43 knapsack Jeannette M. Wing

Pipelining: Doing Laundry 6 hours to do 4 loads 3. 3 hours to do 4 loads Computational Thinking 44 Jeannette M. Wing

Concurrency: Dining Philosophers Five philosophers sit around a circular table. Each philosopher spends his life alternately thinking and eating. In the centre of the table is a large bowl of spaghetti. A philosopher needs two forks to eat a helping of spaghetti. Computational Thinking 45 Jeannette M. Wing

Distributed Computing: The Internet • Asynchronous communication • Failures • Speed of light Computational Thinking 46 Jeannette M. Wing

Distributed Computing: The Internet • Asynchronous communication • Failures • Speed of light Computational Thinking 47 Jeannette M. Wing

Distributed Computing: The Internet • Asynchronous communication • Failures • Speed of light Computational Thinking 48 Jeannette M. Wing

Computational Thinking in Daily Life Computational Thinking 49 Jeannette M. Wing

Getting Morning Coffee at the Cafeteria coffee sugar, creamers soda straws, stirrers, milk cups lids napkins Computational Thinking 50 Jeannette M. Wing

Getting Morning Coffee at the Cafeteria coffee sugar, creamers soda straws, stirrers, milk cups lids napkins Especially Inefficient With Two or More Persons… Computational Thinking 51 Jeannette M. Wing

Better: Think Computationally—Pipelining! coffee soda straws, stirrers, milk cups sugar, creamers lids napkins Computational Thinking 52 Jeannette M. Wing

Computational Thinking at NSF

CDI: Cyber-Enabled Discovery and Innovation Computational Thinking for Science and Engineering • Paradigm shift – Not just computing’s metal tools (transistors and wires) but also our mental tools (abstractions and methods) • It’s about partnerships and transformative research. – To innovate in/innovatively use computational thinking; and – To advance more than one science/engineering discipline. • Investments by all directorates and offices – FY 08: $48 M, 1800 Letters of Intent, 1300 Preliminary Proposals, 200 Full Proposals, 36 Awards – FY 09: $63 M+, 830 Prelimary Proposals, 283 Full Proposals, 53+ Awards Computational Thinking 54 Jeannette M. Wing

Range of Disciplines in CDI Awards • • • • Aerospace engineering • Linguistics Astrophysics and cosmology • Materials engineering Atmospheric sciences • Mathematics Biochemistry • Mechanical engineering Biomaterials • Molecular biology Biophysics • Nanocomputing Chemical engineering • Neuroscience Civil engineering • Proteomics Communications science and • Robotics engineering • Social sciences Computer science • Statistics Cosmology • Statistical physics Ecosystems • Sustainability Genomics • … Geosciences … advances via Computational Thinking 55 Jeannette M. Wing

Range of Societal Issues Addressed • • • Cancer therapy Climate change Environment Sustainability Visually impaired Water Computational Thinking 56 Jeannette M. Wing

C. T. in Education: National Efforts CRA-E Computing Community CSTA NSF Rebooting College Board National Academies Computational Thinking workshops K-12 BPC Computational Thinking ACM-Ed CPATH AP 57 CSTB “CT for Everyone” Steering Committee • Marcia Linn, Berkeley • Al Aho, Columbia • Brian Blake, Georgetown • Bob Constable, Cornell • Yasmin Kafai, U Penn • Janet Kolodner, Georgia Tech • Larry Snyder, U Washington • Uri Wilensky, Northwestern Jeannette M. Wing

Computational Thinking, International UK Research Assessment (2009) The Computer Science and Informatics panel said “Computational thinking is influencing all disciplines…. ” Computational Thinking 58 Jeannette M. Wing

Spread the Word • Help make computational thinking commonplace! To fellow faculty, students, researchers, administrators, teachers, parents, principals, guidance counselors, school boards, teachers’ unions, congressmen, policy makers, … Computational Thinking 59 Jeannette M. Wing

Thank you!

References (Representative Only) • Computational Thinking • Model Checking, Temporal Logic, Binary Decisions Diagrams • – – University of Edinburgh, http: //www. inf. ed. ac. uk/research/programmes/comp-think/ [Wing 06] J. M. Wing, “Computational Thinking, ” CACM Viewpoint, March 2006, pp. 33 -35, http: //www. cs. cmu. edu/~wing/ – [Br 86] Randal Bryant, “Graph-Based Algorithms for Boolean Function Manipulation, ” IEEE Trans. Computers, 35(8): 677 -691 (1986). – [CE 81] E. M. Clarke and E. A. Emerson, “The Design and Synthesis of Synchronization Skeletons Using Temporal Logic, ” Proceedings of the Workshop on Logics of Programs, IBM Watson Research Center, Yorktown Heights, New York, Springer-Verlag Lecture Notes in Computer Science, #131, pp. 52– 71, May 1981. – [CES 86] E. M. Clarke, E. A. Emerson, and A. P. Sistla, “Automatic Verification of Finite State Concurrent Systems Using Temporal Logic Specifications, ” ACM Trans. Prog. Lang. and Sys. , (8)2, pp. 244 -263, 1986. – [CGP 99] Edmund M. Clarke, Jr. , Orna Grumberg and Doron A. Peled, Model Checking, MIT Press, 1999, ISBN 0262 -03270 -8. – [Ku 94] Robert P. Kurshan, Computer Aided Verification of Coordinating Processes: An Automata-theoretic Approach, Princeton Univ. Press, 1994. – [Pn 77] Amir Pnueli, “The Temporal Logic of Programs, ” Foundations of Computer Science, FOCS, pp. 46 -57, 1977. – [QS 82] Jean-Pierre Queille, Joseph Sifakis, “Specification and verification of concurrent systems in CESAR, ” Symposium on Programming, Springer LNCS #137 1982: 337 -351. – [VW 86] Moshe Y. Vardi and Pierre Wolper, “An Automata-Theoretic Approach to Automatic Program Verification (Preliminary Report), ” Logic in Computer Science, LICS 1986: 332 -344. Computational Thinking and Biology – Allessina and Pascual, “Googling Food Webs: Can an Eigenvector Measure Species' Importance for Coextinctions? ”, PLo. S Computational Biology, 5(9), September 4, 2009. http: //www. ploscompbiol. org/article/info: doi%2 F 10. 1371%2 Fjournal. pcbi. 1000494 – Executable Cell Biology, Jasmin Fisher and Thomas A Henzinger, Nature Biotechnology, Vol. 25, No. 11, November 2007. (See paper for many other excellent references. ) – [LJ 07] Predicting Protein Folding Kinetics via Temporal Logic Model Checking, Christopher Langmead and Sumit Jha, WABI, 2007. – Systems Biology Group, Ziv Bar-Joseph, Carnegie Mellon University, http: //www. sb. cs. cmu. edu/pages/publications. html Computational Thinking 61 Jeannette M. Wing

References (Representative Only) • Machine Learning and Applications – – – • Christopher Bishop, Pattern Recognition and Machine Learning, Springer, 2006. [FS 99] Yoav Freund and Robert E. Schapire, “A short introduction to boosting. ” Journal of Japanese Society for Artificial Intelligence, 14(5): 771 -780, September, 1999. Tom Mitchell, Machine Learning, Mc. Graw Hill, 1997 Symbolic Aggregate Approximation, Eamonn Keogh, UC Riverside, http: //www. cs. ucr. edu/~eamonn/SAX. htm (applications in Medical, Meteorological and many other domains) The Auton Lab, Artur Dubrawski, Jeff Schneider, Andrew Moore, Carnegie Mellon, http: //www. autonlab. org/autonweb/2. html (applications in Astronomy, Finance, Forensics, Medical and many other domains) Computational Thinking and Astronomy – – J. Gray, A. S. Szalay, A. Thakar, P. Kunszt, C. Stoughton, D. Slutz, J. vanden. Berg, “Data Mining the SDSS Sky. Server Database, ” in Distributed Data & Structures 4: Records of the 4 th International Meeting, W. Litwin, G. Levy (eds), Paris France March 2002, Carleton Scientific 2003, ISBN 1 -894145 -13 -5, pp 189 -210. Sloan Digital Sky Survey @Johns Hopkins University, http: //www. sdss. jhu. edu/ • Computational Thinking and Chemistry • Computational Thinking and Economics – – – – [Ma 07] Paul Madden, Computation and Computational Thinking in Chemistry, February 28, 2007 talk off http: //www. inf. ed. ac. uk/research/programmes/comp-think/previous. html Abraham, D. , Blum, A. and Sandholm, T. , “Clearing algorithms for barter exchange markets: enabling nationwide kidney exchanges, “ Proc. 8 th ACM Conf. on Electronic Commerce, pp. 295– 304. New York, NY: Association for Computing Machinery, 2007. Conitzer, V. , Sandholm, T. , and Lang, J. , When Are Elections with Few Candidates Hard to Manipulate? Journal of the ACM, 54(3), June 2007. Conitzer, V. and Sandholm, T. , Universal Voting Protocol Tweaks to Make Manipulation Hard. In Proceedings of the International Joint Conference on Artificial Intelligence (IJCAI), 2003. Michael Kearns, Computational Game Theory, Economics, and Multi-Agent Systems, University of Pennsylvania, http: //www. cis. upenn. edu/~mkearns/#gamepapers Algorithmic Game Theory, edited by Noam Nisan, Tim Roughgarden, Eva Tardos, and Vijay V. Vazirani, September 2007, http: //www. cambridge. org/us/catalogue. asp? isbn=9780521872829 David Pennock, Yahoo! Research, Algorithmic Economics, http: //research. yahoo. com/ksc/Algorithmic_Economics Computational Thinking 62 Jeannette M. Wing

References (Representative Only) • Computational Thinking and Law – – The Poirot Project, http: //www. ffpoirot. org/ Robert Plotkin, Esq. , The Genie in the Machine: How Computer-Automated Inventing is Revolutionizing Law and Business, forthcoming from Stanford University Press, April 2009, Available from www. geniemachine. com Burkhard Schafer, Computational Legal Theory, http: //www. law. ed. ac. uk/staff/burkhardschafer_69. aspx Stanford Computational Law, http: //complaw. stanford. edu/ – – – The Diamond Project, Intel Research Pittsburgh, http: //techresearch. intel. com/articles/Tera-Scale/1496. htm Institute for Computational Medicine, Johns Hopkins University, http: //www. icm. jhu. edu/ See also Symbolic Aggregate Approximation, Eamonn Keogh, UC Riverside, http: //www. cs. ucr. edu/~eamonn/SAX. htm – Yubin Yang, Hui Lin, Zhongyang Guo, Jixi Jiang, “A data mining approach for heavy rainfall forecasting based on satellite image sequence analysis. Source, ” Computers and Geosciences, Volume 33 , Issue 1, January 2007, pp. 20 -30, ISSN: 0098 -3004. See also Symbolic Aggregate Approximation, Eamonn Keogh, UC Riverside, http: //www. cs. ucr. edu/~eamonn/SAX. htm • Computational Thinking and Medicine • Computational Thinking and Meteorology • – Computational Thinking (especially Machine Learning) and Neuroscience – – – • Yong Fan, Dinggang Shen, Davatzikos, C. , “Detecting Cognitive States from f. MRI Images by Machine Learning and Multivariate Classification, ” Computer Vision and Pattern Recognition Workshop, 2006. CVPRW '06, June 2006, p. 89. T. M. Mitchell, R. Hutchinson, R. S. Niculescu, F. Pereira, X. Wang, M. Just, and S. Newman, "Learning to Decode Cognitive States from Brain Images, "Machine Learning, Vol. 57, Issue 1 -2, pp. 145 -175. October 2004. X. Wang, R. Hutchinson, and T. M. Mitchell, "Training f. MRI Classifiers to Detect Cognitive States across Multiple Human Subjects , " Neural Information Processing Systems 2003. December 2003. T. Mitchell, R. Hutchinson, M. Just, R. S. Niculescu, F. Pereira, X. Wang, "Classifying Instantaneous Cognitive States from f. MRI Data, " American Medical Informatics Association Symposium, October 2003. Dmitri Samaras, Image Analysis Lab, http: //www. cs. sunysb. edu/~ial/brain. html Singh, Vishwajeet and Miyapuram, K. P. and Bapi, Raju S. , “Detection of Cognitive States from f. MRI data using Machine Learning Techniques, ” IJCAI, 2007. Computational Thinking and Sports – – Synergy Sports analyzes NBA videos, http: //broadcastengineering. com/news/video-data-dissect-basketball-0608/ Lance Armstrong’s cycling computer tracks man and machine statistics, website Computational Thinking 63 Jeannette M. Wing

Credits • Copyrighted material used under Fair Use. If you are the copyright holder and believe your material has been used unfairly, or if you have any suggestions, feedback, or support, please contact: jsoleil@nsf. gov • Except where otherwise indicated, permission is granted to copy, distribute, and/or modify all images in this document under the terms of the GNU Free Documentation license, Version 1. 2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front. Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled “GNU Free Documentation license” (http: //commons. wikimedia. org/wiki/Commons: GNU_Free_Documentation_License) • The inclusion of a logo does not express or imply the endorsement by NSF of the entities' products, services or enterprises Computational Thinking 64 Jeannette M. Wing